Automatic hammer



H. L. GASKILL AUTOMATIC HAMMER Jan. 6, 1953 4 Sheets-Sheet l Filed Jan. 16, 1950 IN VEN TOR. ly'/IRRYL GAS/ULL AGENT Jan- 6, 1953 H. l.. GAsKlLL 2,624,047

AUTOMATIC HAMMER Filed Jan. 16, 1950 4 Sheets-Sheet 2 IN VEN TOR.

851/1 RRY L. @ASK/L AGENT H. L. GASKILL.

AUTOMATIC HAMMER Jan. 6, 1953 4 Sheets-Sheet 3 Filed Jan. 16, 1950 JNVENToR. BYf/{RY L GSK/LL ,glil

AGENT -4 Sheets-Sheet 4 H. L. GASKILL AUTOMATIC HAMMER Il wi Jan. 6, 1953 Filed Jan. 16, 1950 QW WW INVEN TOR.

AGENT HARRY L- @ASK/LL Patented Jan. 6, 1953 UNIT STATES QFFICE Y l2,624,047 I AUTQMATIC HAMM@ Harry. L? Geelen Freiheit @ree- .nppiicatiou 'January' 1e, 195.0,.seria1 4..iv..,7l3 7,

itfleire- (Gli 1749 The invention .relate.s..to.tQQlS for driving .fastemine devices, and itparticularly pertains to .a self feeding automaticnanimer ier driving ttf-telas Automatic hammers :having various minis .Qi rackfand-pinion or leuendrive means .areliilfivin to the art but these arrangements are nossestd of several interrelated disadvantages among the most outstanding ofwhchare, high, cost onfniannfacture, susceptibility of.. breakage. vland QOmPlexity of repair, gall of .which .add 1113.159 high ORSI' ating costs.

It is an object ofthe invention to provide an automatic hammer .having .a .hydraulic drive means whereby the above mentioned disadvantages are overcome.

It is another. .object of. the invention toprQYide an .automatic hammer. 1in. accordance ,with ...the foregoing objectthat has aminimurn ofmoving parts and is inexpensive qmanufactura It is .a further. object of. theinvention to vprovide an. automatic hammer in accordance ,with the foregoing, Objectsthat .can .be disassembled with a minimum of `tools .or inspection `and maintenance.

.Theseand other objects of the invention VVwhich will appear as the. specification .prcnrressesY are attained in antautomatic-hammer having a hydraulic actuated .driving ymember .arranged to driven fastening device into: the ,Werk in response to the force exerted .by a Work striking `lllember against the work; thework.strikingmemberbeing4 coupled tothe .driving member by, hydraulic link means arranged to. reverse the` efectivedirection of force andalso. tosabsorb. ythe initial shok. More vspecific objects ofthe. invention are attained in an. automatic `hammer for driving staples, which hasa rigidonstruction and vreadily Vdemountable component parts.

The inventionwill be..described,in detail .with reference to the accompanying ,drawing forming a part of the specication and in which:

Fig. 1 is a front view of .an automatic hammer according -to the invention;` Eig. .1(4) is a. crosssection viewof the arrangement shown in rFig- 1 rtalfrenalong the line law- La;

vFig- 2 iS a smelten/partly .in crossrsection taken alongl .the line'42-,- 2, offthe hammer. according to the intention shown inFg. l;`

tra .n einen "ths partly in mss-.section v irnt Qrianlautomatic ham er' according tlie u'iv rition; Figa isadetaued jrview 'or portion of the arraneemeiit'ofirir; i .'igglismfaw exploded yiew of pertinent parts ofmthe alternate" mb" mentsj"and"""" Figslrn): "10. dilute)` 'are consecutive illustrations Qf'th .mfie "of "operation of the automa ehainnie aecqrdins theinvenuon; "Ref 'ing" tdriig'sl -2 and 3 ,tirareisr 'shown an'a'utomtie'hammler a 'dingftothe invention iorwdriving' a "desifr'ed typ .f S'tener; sh-'ownf here as' a stain f a; although u; `siiiieuliliiL ,be una-erstem c "f' the" invention to provide for the rd r of ahyhf the' headless typevsmof as'teningjdev ces,1seh 'as pins', corner-A fa'stlfferSQv ad" ftli '1111?5'"bd'y"A member l 2 pf the .lfiainer` l"'.p'ieferaldly vinade .frm' heavy gageL Vsheetmetal'stanrped"1andTfhlded into a uishaiiii member .hat-ing arbottom' wan 'la of unifornril Width .'.and "side walls vI6;I l1 which are mw in .nei'ehtrorith greater. part of the length pfbody member' ITOrnritli' base of a handle portion. i8 and 'Whiehfae'frelativ'ely high'for the renainder'offlnjdyv ume kidenl'2"fming the base of thefhe'ad portion" 9 `f the hammer. Staples Il) aearrangedin'a" agaz'ie,20,`a"part of'which located .within 'handle portieri' ls and the remainder of .Whichismlo'c/ated `head portion l B063!` member T2'.- and'inagazine' 20 may I be" constructed 'inV accordance vtvitl'ikn'oWn arrangements, the inven'tnA not" liengdir ectly` concerned therewith. inthe preferred embodnnenumagazine: .2e

' ea portiony l 31 'solely by means of a pin 34 passing through apertures 34 in side walls l5, |1 and apertures 34" in guide plate t2 in a well known manner; and guide plate 32 is accurately aligned with guide block 22.

In the hammer according to the invention staples I are forced down through staple slot 30, formed in the front wall of guide plate 32 at one side of which an end of guide block 22 acts as a closure, by means of a conventional steel blade 4B having dimensions in accordance with standard machine shop tolerances to enable it to travel smoothly in slot 30. The motive power for activating blade 40 is obtained according to the invention by the relative upward motion of a striker 42 caused by the entire device being swung down onto the work in the same manner as the conventional hammer. Striker 42 moving upward relative to side walls I5, |1 forces a piston 44 having an annular cross-section up inside a cylinder 46 which is rigidlyattached to the hammer by means of screws 49 (only one of which is shown) threaded into a strut 49 which is fastened to side walls I6, I1 'by screws 49. The upward movement of piston 44 displaces a Volume of substantially incompressible hydraulic fluid which is interposed in the annular space 48 of cylinder 45. Piston 44, shown in cross-section in Figs. la and 2, has a thick walled tubular configuration with a bifurcated lower portion forming connecting rod portions 50, 5| as perhaps more clearly illustrated in Fig. 3. A ram 52 having a cylindrical plunger portion 85 arranged in the bore of piston 44 is driven downward relative Ito`side walls IB, l1V by action of the hydraulic fluid in space 48 in accordance with well known hydraulic laws. Ram 52 is rigidly fastened at the lower end portion 82 to blade 40. Thus staple I0 is driven into the work by action of striker 42 being forced against the work. Once the staple I0 is driven, ram 52 and blade 4Q are returned to the initial position by the action of a coil spring 55 exerted against a strut 58 arranged between sidewalls I6, l1. The return of ram 52 and blade 40 `may be used to force piston 44 to Aits initial position, but it is Yconsidered desirable to assist this motion by 4means of compression spring arranged incylinder 46.

Preferably a V-shaped annular groove 62 is cut into the top surface of pison 44 as shown in the cross-section view .of Fig. 2 to form a seat for spring 50. The uppermost end of cylinder 46 is preferablyv constituted by a removable plug 64 having a threaded shoulder although a cap arrangement is also suggested. While cylinder 45 may be fil-led with fluid by removing plug 54, a filler plug 66 of smaller dimensions is preferably provided. Piston 44 and ram 52 are fitted with grooves 15 and 12 respectively to accept oil sealing rings of resilient material, such as the Koroseal oil rings now commonly used for such purposes, to prevent leakage of the substantially incompressible hydraulic uid which is usually in the form of a liquid such as light mineral or petroleum base oil.

Striker 42 is made of heavy sheet steel stamped to form a generally U-shaped member having two ears extending upwardly from the sides thereof as shown in the forepart of Fig. 3, leaving a low throat at the front part `of the striker 42, which allows access to the lower portion 82 of ram 52 for manually moving blade 40 in clearing jams and the like. Striker 42 is connected to piston 44 at the ends of rod portions 50, 5| by means of wrist pins 14, 15 and is guided in' its movement by pin 34 riding in slots 16 machined in striker 42, Pin 34 is made removable so that in case of jamming striker 42 may be rotated about wrist pins 14, 15 in the direction of the arrow to provide access to staple slot 30, guide plate 32 then being conveniently removable.

A top plate 11 is fastened to bear on the upper edge of side plates l1 by machine screws 49. Top plate 11 is electivein limiting travel of ram 52 which is machinedy from a square bar to have a square end portion 82, a cylindrical plunger portion 80, and an undercut central portion SI which passes through an aperture 18 in top plate 11. In the illustrated embodiment, ram 52 is made in two pieces, as shown in Figs. 2 and 3, and fastened together by a pin 83 after passing through top plate 11, although alternate construction, such as thatlater to be described in connection with Fig. 7, may be used. Ram 52 is limited in its downward movement by the shoulder 85 of the'plunger portion 8B striking top plate 'l1 and limited in its upward movement by the square shoulder 85 of square portion S2 striking the underside of top-plate .11. Piston 44 is limited in its downward movement by top plate 11 striking the flat surface 81 on the underside of piston 44 between the connecting rods-50, 5|.

Referring to Figs. 4-9, there is shown an alternate embodiment of a hammer according to the invention which incorporates a number of additional advantageous constructional features. The handle and body are formed in much the same manner as the previously described hammer, and the staple feed mechanism is essentially the same, hence these parts will not be discussed in detail. A cylinder |46 having an extended portion in which there is located a rectangular slot |45' having edges |45 spaced to accommodate the width of body member H2, is welded along edges |49 to side walls ||5,-||1 as shown. The lower end of Vcylinder |46 is preferably mitered as shown to permit ready access to the blade at the front of the hammer and also to provide a more pleasing appearancel The uppermost end of cylinder |48 is fitted with a plug |64 and filler plug |56 as in the previous description of the basic embodiment. vA unitary 'piston-striker |4| comprising a striker portion |42 and a piston por- 'tion |46 joined by strut portions |55, |5| is machined in one piece as shown in Figs. 4-6 which makes for a stronger'and smoother` acting tool. A cross-section of piston-striker |4| showing the shape of the connecting rod portions |50, I5|

taken along the line 5-5 is shown in Fig. 5, and a cross-section of the striker portion |42 taken along the line 6 8 is shown in Fig. 6. Ram |52 is constructed in one, piece with a cylindrical plunger portion |80, and a central portion |8| preferably undercut on three sides only to proviole a greater surface bearing on a travel-limiting strut |11 which is welded between side walls H6, ||1. The details of ram |52 and blade |40, together with the relationship thereof to the head portion of body member |I2, maybe obtained from an inspection of the exploded view of these parts in Fig. 9. Strut |11 has a U-shaped notch |18 in the forward edge thereof in which the undercut central portion I8| of ram |52 fits.

With such construction the hammer is assembled by rst inserting ram |52 down from above into cylinder |46 ahead of strut |11 and partly in the space provided for piston |44 and then moving it to the rear to engage theundercut central portion I8| in the U-shaped notch |18 of strut |11, at the same time inserting spring |56 between ram |52 and-strut |58,fa'fspace=`for 4*which isf-preferably lprovided -xin 4'th'elcsvver part of `Aram I 52 'to permit a foreshortenedconstructionethereof. APiston-striker 114| is next -inserteddown'from above vinto cylinder I6 around-"ram I'|352 and fengaging' dpins |34 on either iside ofb'od'y v`| I2 in grooves 'I6 vvvtofguide j'and Vlimit ftravl-'fo'pistonstriker Htl. "Ih'eblade |540 rides "-in/ehannel' of striker portion HM-2 'of piston-striker |-4|, so that the latterforms'in eie'ctthe fronti-guide plateco'rresponding to gui'de 'plate 32 ofthe'rst embodiment. Spring 6U is positioned yand plug llput vin place Ato Lliold the parts together. The hydraulic liquid is "added by *way 'of "jtlfi'eV ller aperture, which zisithene-Lclo'se'd Lby thefller plug |66.

In case -of ljams the'hammer asshownlinFig. 7 may readily be disasse'r'nbled inrever'senrder-"to the lassembly Vpreviously described, however, Vva. betterjconstruction Vfor -clearing jams is 'shownfin Figs. 8 and 9, wherein-'there iss'hown an embodimentV having a removable iguide lblock =assembly |22. 'A'portionof bottomwall "l'llleand-side 'Walls IFB, are cut away'a-nd'fa Achannel member |22 carrying guide block 22 'is inserted lin their stead to'c'omplete the'hammer as'before. kifissembly v| 22 is Aheld in place at the vfdrwardfendby V'arcuate lugs N engaging `complementa-ry*notches |41, the front edges |41 V of `which :are swept forward to permit rotation of theA whole lassembly r|22 as shown in dotted lines `in-Fig. 8 to Y'permit insertion and removal. Since practically the `only force exerted against 'block 22 is'atthe forward end'where the staples `t'ilareejected -by'blade Mu, a simple bullet catch `|`5| under the "ivn'iiuence oi spring |52 serves to *holdfassemblyf |22 in place. Catch |-5| and spring |52 larefco'mv/eniently arranged inside channel member 2| of -staplemagazine 228.

' Referring to F'gs."10(a') 10(1)) 'allld'lQtC there is shown a series of views illustrating fthe-mode of operation of thelautomatic hammer*according to the invention. In these guresfthe embodiment `of the vinvention 'shown' in Figs. '1l-T9 Ahas been chosen for oonvenience,fbut l'it A'should' be vclearly understood `that *the principle of uoperation applies lequ'allyi'well to the embodiment shown in Figs. 1, lfd), 2"al1d'3. "In Figs.V u'10*(`1),""10`(b) and `1O(c) only those-"parts 'directly y'concerned with thefn'ovel Yoperating features" o'f the "inven- 'tion are vshown :inthe interest oficlar'ity.

Assumingthat itis desiredto :staplea 'card |8| lto a lboard'iSZ, the'ha'mmer `is Vbrought Vdown onto the'work 'comprising 'the card |8| on 'board |82 inexac'tly the 'samefmannerlas would be done with an altogether conventional hammer. 'As the hammer according tothe invention'lapproaches and just touches the work as shownfinFig. 10`(a) representing vthe vhammer `in"'tli`e initial operating o position, piston-Striker |4| "is at -l'the llowerm'ost position with respect 'to 'body member "I |2 and ram l| 52 is at the uppermost position. "Staple v||l is suspended in feed .slot 'I`3fbelowfbl'adeH0 by the glue Vholding staple `Il) tostaples TID i'n' the staple Astick which islljgedfoIwardfby fol-lwer 24 Yunder the influence of v spring V26. {"(The'latter parts are'no't shown 'in'Fg l0 (a) but are "shown in 'Fig v2.) For c'larit'y,` "staple Hl "islshvvnin crosssection while staples IU' are "shown"in"`ful1 elevation,l

As thehammer acoor'dingftothe invention continues 'to be forcedv against `the' work.l b'odyjmemberl I2 is moved downward with-respect to piston- :stnker Y|11 l as Ashown infine. -1'0 di) I`repmsemting 'the hammer man` 'intermediate operatingV 'position, carrying cylinder M6 downward vwith 7it. Piston portion Y:HMI of vListon^-str'ik'er |f4f| r'thereby rises within Vcylinder |"4'6 4Iand forces ram |52 downward with respect to bod-y memb'er l'l 2 and cylinder |46 due tothereaction of Ithe substantially incompressible -Iiuid iin f'spac'e (|48. i'IIhe downward 'movement'f-of fram '|52 and blade |40 with respect to body member H9 fshe'ar's staple I0 :from the staple fstick and forces .it into the work beneath blade 1140.

At the end of Athefstrok'eas shown -in-Fig. 10Go) representing the hammer 'inthe nn'al .operating position, piston-striker |4| is still in contact with card |8| and bodymem-oer I'izis atffthe lowermost position relative thereto. .lPListon -`portion te 4l of Vpistonstrikerllfll| islthereforeiattheimaximum fupwarl position wthin'cylinder r:|6.1.and ram |52-along withblad'e |41! is-at'th'e'l'maximum downward limitofftravel, preferably"bemgiimited thereat by strut 111,' and staplel'l'llfis icompletely driven into fthework.

Upon lifting-the `lhamme1-aocording tothe .invention. the-combinedfspringandhydraulicaetion causes thevparts toresume the initi'alposition .las shown in Fig. `10 (a) vin readiness .for the next blow.

While the invention has-been'describedzin terms of `express embodimentsfit isvto'beiclearily understood 'that' I many fobv-iolus modifications lof'm'inor parts thereof will be suggested byl-tho's'e .skilled in the art Without ldepartingfrornfthe..spirit 'and the scope of Ythe invention.

The invention claimed-is:

l. A staple drivingfdeviceincluding a ...body member vhaving a head portion at Yone-end` thereof 'anda lhandle porftion, said head portion oomprising-a support including spaoed'uprightmembers, a top-member-'car-ried by said uprightmembers, a cylinder mounted Ion saidtopmemb'erand closed at the end thereof remote 'from-"Saidtop member, a piston having a central bore therein and connecting rod portions fsl-idablyv-Iarranged in said cylinder with said-connecting 'rodportion's straddling the head-portionof -said body'me'mber, a striker mounted "for upward "and `downward movement beneath said piston, 'said "strikerprojectingbelow saidbody' member vand being lpivot- 'ally connected to'said 'connecting 'rod'p'ortions of said piston, 'means attached to Vsai' 1l"upright members to form a '-guideway, fori-a fstaple, a -driving blade 'positioned in said fguideway, va 'ram aliixed to saiddrivin'gblade and positioned in the bore of `said piston to close the chamber formed at the closed end of saidcylinderlby said piston, said chamber being lledwitha substantially incompressible fluid .operable to-shift said ram and said driving fblade downward ito drive a staple through said g'u-ideway'in response to upward movement .of `VAsaid striker fand said piston asa result of ablow against anobje'ct by said striker, andmeans-to feed staples to the driving position.

`2. A device for drivingY fa'steners,l-including-a body member, -a cylinder mounted on said body member `a'nd closed at-'the t'end''-the'reflremote from said body member, 'fa piston `having La central bore therein 'Land dametrically opposed connecting rod portions, said piston being slidably mounted within'said cylinder "with saidzconnecting rod portions straddlingsaidzbodytmember, 'a' striker mounted onxsa'idbody .member and arranged for upward downward :movement beneath said piston, said striker `.projecting :below-said body member vand'being connected. .to

said connecting rod portions ofr Saidpistonmeans vwithin said'bodymember toI-formafguideway :for

a fastener to be driven, a driving member positioned'in said guideway, a ram affixed to said driving member and slidably positioned vin the bore of said piston to close the chamber formed at the closed end ofsaid cylinder by said piston, said chamber being lled by a substantially incompressible fluid operable to shift said ram and said driving blade downward to drive av fastener through said guideway in response to upward movement of said striker and said piston as a result of a blow against an object by said striker. and means to feed fasteners to the driving position.' Y

3; A staple driving device including a handle portion, a striking hea-d portion including a body member secured to said handle portion, an upright striking element slidablymounted on said body member, means arranged on said body member and within said striking element to form a guideway for a staple, a cylinder mounted on said body member above said striking element, said cylinder being closed at the end remote from said striking element, a pistonhaving an internal bore therein slidably arranged in said cylinder, means interconnecting said piston with said striking element, said striking element projecting below said body member, a driving blade slidably positioned in said guideway, a ram affixed to said driving blade and positioned in the bore of said piston to close the chamber formed at the closed end of said cylinder by said piston, said closed chamber being lled by a substantially incompressible fluid operable to shift said ram and said driving blade downward to drive a staple through said guideway in response to upward movement of saidstriking element and said piston as a result of a blow against an object by said striking element, and means arranged within said handle portion to feed staples to the driving position.

4. A staple driving device including a handle, a staple guide barmounted in and extending longitudinally of said handle, means for feeding staples along said bar to the forward end thereof, a striking head portion at the forward end of said handle including spaced upright side plates, a top plate carried by said side plates, a cylinder mounted on said top plate and closed at the upper end thereof, a piston having an internal bore therein slidably arranged in said cylinder, a striker mounted for upward and downward movement beneath said piston at the forward end of said bar and providing therewith a guide- Y way for a staple to be driven, said striker projecting below said striking head portion in striking position, a driving blade arranged to slide in said guideway to drive a staple therethrough, a ram aixed to said driving blade and positioned in the bore of said piston to close the chamber formed at the lower end of said cylinder by said piston, said chamber being filled by a substantially incompressible fluid operable to shift said ram and said driving blade downward to drive a staple by upward movement of said striker and said pistonV by a blow against the lower end of said striker against an object.

5. A staple driving device including a body member having a head structure at one end thereof and a handle structure at the other end thereof, a vertically slidable striking element arranged on said head structure at the front of 'said body member, said element projecting at the lower end thereof below said body member, means within said head structure providing a guide for 'a staple, a stapledriving blade slidably arranged in 'said guide means, a cylinder having one end thereof closed aligned with said striking element and affixed to said body member, a piston having a central bore and being mechanically coupled to said striking element to move up and down in said cylindera -ram arranged in said .piston and mechanically coupled to said driving blade, saidram closing the chamber in the closed end of said cylinder formed by said piston, said chamber being filled with a substantially incompressible fluid operableby upward movement of said striking element and said piston as a result of a blow against an object to shift said ram and said driving bladev downward to drive a staple through said guide means, and means for feeding staples to the driving position.

6. A staple driving device including a body member, a striking element slidably mounted on one end of said body member and protruding therebelow, a cylinder mounted on said body member above said striking element, a piston element slidably arranged in said cylinder and having an internal bore, connecting rod elements joining said striking and said piston elements for simultaneous movement thereof, means within said body member and within said striking element forming a guideway for a staple,V a blade element slidably arranged in said guideway, a ram element slidably arranged in the bore of said piston thereby closing one end of said cylinder, a member connecting said blade and said ram elements for simultaneous movement thereof, the other end of said cylinder being closed to form a chamber thereat, said chamber being filled with a substantially incompressible fluid operable to shift said ram and said blade elements downward to drive a staple through said guideway in response to upward movement of said striking and said piston elements as a result of a blow on the protruding end of said striking element against an object.

7. A staple driving device including a body member having a head structure at one end thereof and a handle structure, a vertically slidable striking element arranged on said head structure at the front of said body member, said element projecting at the lower end thereof below said body member, means within said head structure providing a guideway for a staple, a staple driving blade slidably arranged in said guideway, a cylinder having one end thereof closed aligned with said striking element and affixed to said body member, a piston having a central bore and being mechanically coupled to said striking element to move up and down in said cylinder, resilient means in said cylinder urging said piston downward, a ram arranged in said piston and mechanically coupled to said driving blade, further resilient means arranged between said body member and said ram urgingsaid ram upward, said ram closing the chamber formed in ythe closed end of said cylinder formed by said piston, said chamber being filled with a substantially incompressible fluid operable by upward movement of 4saidstriking element and said piston as a result of a blow against an object to shift said ram and said driving'blade downward to drive a staple through said guideway, and means arranged in said handle structure for feeding staples to the driving position.

8. A staple driving device including a body member having. a head structure at one' end thereof and a handle structure, a vertically slidable piston-striker unit arranged on said head .structure .at the front of said body member, said l gegane? piston-striker unit projectingJ at the; lower4 end thereof below said body; member andf-attheupper end-thereof-` above saidbcdy member, means withinsaidhead structure and coacting with` said piston-striker uni-ty toY form a guidewayfor a staple, astaple'driving blade slidably arranged in said guideway, a cylinderhaving one end thereof closed and being affixedl to` said body member, saidcylinder surrounding the upper end of said piston-striker unit, said upper end of vsaid pistonstriker having a-centralbore., ara-m slidablyv arranged in the central bore of saidpiston-striker unit andbeing mechanically coupled to. said driving` blade; said ram.. servingY to close the. chamber formed inA saidy cylinder by said piston-striker unit, said chamber being. filled with afsubstantially incompressible. liquid.. Operable by upward movement ofv said piston-strikerl unit as. a, result of a. blow against. an objeotto shiftsaiol ramand said driving blade downward to. drive a staple through. said guideway, and'. means for feeding st'aplesto thedrivingpositi'on.

9;. A fastener' driving device including a. body member, a striking elementv slidably mounted on said body member and!- protruding therebelow, a cylinder mountedV on said' body member above said striking element, a piston element slidably arranged insaid cylinder and having an internal bore,.m'embers connecting said striking and said piston elements for simultaneous movement thereof, means withinv said body member and within saidstriking'element"forming a guideway for a fastener, a bladeelement-slidably arranged in said guideway, a ramj element slidably arrangedin ther bore of said' piston thereby-closing onel end of said cylinder, a furthermemberl connectingrsaid bladeA and said ram elements for simultaneous movementy thereof, the other end of saidY cylinder being closed to form ay chamber thereat, said chamber being` adapted toreceive a quantity of substantially incompressible fluid operable to shift said-ram and-saidbl`adeelements downward to drivea fastener through said guide- Way in response to upward movement of said striking and, said pistonV elements as a result of a blow on the protruding end of said striking element against an object.

10. A staple driving device including a handle, a head structure at one end of said handle including side plates secured to lsaid handle and a vertically slidable striking element mounted on said head structure and projecting therebelow, means within said head structure providing a guideway for a staple; a stapledriving blade within said head structure and slidably arranged in said guideway, a cylinder aligned with said striking element and aiiiXed to said head structure, a piston having a central bore and being connected t said striking element to move up and down in the lower part of said cylinder, a ram arranged in said piston and connected to said driving blade, said ram closing the lower end of said cylinder, a plug member closing the upper end of said cylinder to form a chamber thereat, said chamber being filled with a substantially incompressible liquid whereby upward movement of said piston resulting from a blow against an object by said striking element serves to Shift said ram downward to drive a staple through said guideway beneath said driving blade, and means to feed staples to the driving position.

11. A staple driving device including a handle, a guide bar in said handle, a striking head structure at one end of said handle including upright walls spaced by strut members, a vertically slidable striking element arranged on said upright walls of: said head structure atthe frontthereof for reciprocating movementthereomsaidl striking element yprojecting at the lower endV thereof below said handle, means, forming a` partot said head structure and4 ooactingl with. said guide. bar to provide aguide for a staple to `be driven, a staple driver arrangedv for reciprocating. movement. in said guide means, a cylinder having the upper end closed andbeing. afxed to said' upright walls in line with. said striking. element, a piston having anv internal bore and being connected to'said striking, element for reciprocating movement in vsaid cylinden. a spring in said cylinder tending to. force. said piston down andretractsaid striking element, a ram arranged for reciprocating movement',` in said piston and coupled to said staple. driver,- another spring bearing against one of saidV strut members andsaid ram tending to force said Vram upward and retract said staple driver, said ram closing a chamberv in` the upper end` of said cylinder formed' by; said piston, said chamber being filledl with a substantiallyv incompressible liquid operable' by upward force of' said striking elementV and said piston resultingfrom a blow againstA an object byv 4said striking element to shift said ram andY said staple driver downward to drive a staple through said'- guide means, and means for feeding staples along said barv to the driving position.

12. A staple driving devicehaving a body member,l a striker member arranged on said body member for reciprocatingv movement, said striker member normally projecting beyond said body member, a guideway for a staple to be driven arranged within saidbodymember, a staplefdriving blade arranged for reciprocatingy movement in said guideway, ahydraulic leverl arrangement comprising a cylinder member, and a pair of piston members arranged' for concentric reciprocating movement! inl ysaidcylinder member',v said cylinder memberbeing afxedto said' body member, one, of said piston members being coupled to saidy strikerV4 member and the other being coupled tosaid staple driving'blade, said cylinder member being lledwithfasubstantially incompressible'liquidoperable to-force saidf staple driving blade through said guidew'ayfby vpressurev on said' other: pistony member in` response to movement of said one pistonmemb'er as-a result.' ofa blow againstA an object by2 said striker. member forcing said onev piston member' in a direction opposite to the direction off forceen said staple driving blade;

13. A stapledriving devicezhavinga bo'dyfmember, a strikerA member' arranged on said body member for reciprocating movement and extending beyond said body member at one extremity of said movement, a guideway for a staple arranged in said body member and parallel to the direction of said movement, a staple driving blade arranged for reciprocating movement in said guideway, hydraulic means arranged to reverse the direction of force obtained from movement of said striker member as a result of a blow against that portion of said striker member extending beyond said body member by an object to force a staple through said guideway before said driving blade, said hydraulic means comprising a casing and a pair of piston members arranged for parallel reciprocating movement in said casing, one of said piston members being coupled to said striker member and the other to said driving blade, said casing being connected to said body member, and a quantity of substantially incompressible liquid filling' said casing.

14..A staple driving device including a body member, means within said body member form ing a guideway for a staple, a tubular member positioned above said guideway and aixed to said body member, the top of said tubular member being closed, a tubular element slidably arranged within the lower part of said tubular member, a striker element arranged on said body member for upward and downward movement, means coupling said striker and said tubular elements for simultaneous movement thereof, a ram member slidably arranged within said tubular element, a staple driving blade arrangedfor downward and upward movement in said guideway, means connecting said ram and said staple driving members for simultaneous movement thereof, the upper part of said cylinder being filled with a substantially incompressible liquid operable in response to a blow against the under part of said striker element forcing said tubular element upward in said tubular member to shift said ram member downward to drive a staple through said guideway before said staple driving member.

15. A staple driving device having a body member, a striker member arranged on said body member at the front thereof for upward and downward movement, a guideway for a staple to be driven arranged within said body member, a staple driving blade arranged for downward and upward movement in said guideway, a hydraulic mechanism comprising a casing member affixed to said body member and having the upper end thereof closed, a pair of piston members movably arranged in said casing member, one of said piston members surrounding the other and having an extended portion projecting below said casing member and connected to said striker member, the other of said piston members being connected to said staple driving blade, said casing member above said piston members being filled with a substantially incompressible liquid whereby said staple driving blade is forced downward to drive a staple through said guideway by down- -ward movement of said other piston member in vresponse to upward movement of said one piston member as a result of a blow against an object by said striker member, a staple guide bar arranged to feed staples to said guideway, and

means for removing an end portion of said staple guide bar adjacent said guideway.

16. A mechanism for driving fastening devices including a body member having means forming a guideway for a fastening device to be driven and means to feed fastening devices to said guideway, a, fastening device driver arranged for reciprocating movement in said guideway. a work striker member arranged on said body member for upward and downward movement in the general direction of said guideway, hydraulic means for control of said driver by said work striker member comprising a chamber member ailixed to said body member, a pair of piston members movably arranged in said chamber member, one of said piston members being coupled to said work striker member and the other of said piston members being coupled to said fastening device driver, said chamber being arranged to be filled by a substantially incompressible fluid whereby a fastening device is driven through said guideway by said driver by movement of said other piston member in response to hydraulic pressure applied by said one piston member as a result of a blow against an object by said work striker member.

1'7. A staple driving device including a body member, a guideway for a staple to be driven affixed to said body member, a staple driving member arranged for reciprocating movement in said guideway, a work striker member arranged on said body member for reciprocating movement in a direction parallel to said staple driving member and partly surrounding said staple driving member, a chamber element aixed to said body member, a pair of piston elements movably arranged in said chamber element, one of said piston elements being coupled to said staple driving member and the other being coupled to said work striker member, said chamber being arranged to be filled with a substantially incompressible fluid whereby a staple is driven through said guideway by said staple driving member by movement of said one piston element in response to hydraulic pressure applied by the other piston member as a result of a blow against an object by said work striker member.

HARRY L. GASKILL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,345,267 Keil Mar. 28, 1944 2,412,620 l Kipp Dec. 17, 1945 2,482,993 Walker Sept. 27, 1949 2,537,601 Y Peterson Jan. 9, 1951 

